Bicycle rollers are well known devices for supporting a bicycle and permitting a user to mount and ride the bicycle with the rear wheel rotatably supported by a pair of rear rollers and the front wheel rotatably supported by a single front roller. Motion permitting bicycle rollers include the above described device mounted on wheels or some other motion permitting assembly, so that the rollers and bicycle can move slightly forward and rearward during use, limited by a motion-resisting assembly. To provide a realistic riding sensation, the motion-resisting assembly must permit from 5 to 10 cm of forward and rearward movement, gently resisted and urged back to a center point. To achieve this goal, some currently available systems include an outer frame, which provides a stationary track for movement and an anchor point for one or more elastic members (“bungies”) which gently resist the movement. This produces a far more realistic sensation of bicycle riding. Also, however, it is virtually impossible to build an easily collapsible assembly, using this basic structure, because of the two frames.
Whether motion permitting or not, currently available bicycle rollers connect the front roller and rear rollers with a pair of structural rails running along the sides of the rollers about 15 cm off the ground, suspending the rollers above the ground and carrying the weight of the cyclist. Accordingly, these rails present a trip hazard to the user mounting or dismounting from a bicycle mounted on the rollers. When a rider loses his balance and must dismount very quickly, these rails present a particular hazard.
With respect to motion permitting rollers, the current designs tend to be somewhat heavier than would be ideally desirable, and are not collapsible, for easy transport.